Germ cell ovarian cancer
From Wikipedia, the free encyclopedia
| ICD-10 | C56. |
|---|---|
| ICD-9 | 183 |
| ICD-O: | 9060-9100 |
Germ cell ovarian cancer is a rare form of ovarian cancer: approximately 5% of ovarian cancers are classified as germ cell. Treatment is often by chemotherapy drugs that are similar to those used in the treatment of testicular cancer.
Germ cell neoplasms arise from the germ cell elements of the ovary and include dysgerminoma, endodermal sinus tumor, embryonal cell carcinoma, choriocarcinoma, teratoma, polyembryona, and mixed germ cell tumors. Unlike the epithelial neoplasms, which tend to occur during the sixth decade of life, this group of tumors tends to occur during the second and third decades and as a group is associated with a better prognosis. Many of these neoplasms produce biologic markers, which can be monitored to assess response to therapy.
Germ cell tumors are derived from the primordial germ cells of the ovary. Whereas malignant germ cell tumors can arise in extragonadal sites, such as the mediastinum and the retroperitoneum, the majority of germ cell tumors arise in the gonad from the undifferentiated germ cells.
Ovarian Germ Cell Tumors can be divided into three major groups: (1) benign tumors (usually dermoid cysts); (2) malignant tumors that arise from dermoid cysts; and (3) primitive malignant germ cell tumors including dysgerminoma, yolk sac tumors, immature teratomas, embryonal carcinomas, and choriocarcinoma.
Dysgerminoma of the ovary is the female counterpart of the seminoma in the male. It occurs primarily in young females and accounts for about 30-40% of germ cell tumors. Grossly, the tumor is rather rubbery in consistency, smooth, rounded, and thinly encapsulated, with a brown or grayish-brown color. This neoplasm is unilateral in 85-90% of cases. It is a solid neoplasm, which may contain areas of softening due to degeneration.
Histologically, dysgerminoma mimics the pattern seen in the primitive gonad, ie, it has nests of germ cells that appear as large, rounded cells with central nuclei that contain one or two prominent nucleoli surrounded by undifferentiated stroma (Fig 49-6). Lymphocytes may invade the stroma and occasionally giant cells are identified. A lymphocytic infiltrate is considered a favorable prognostic indicator.
Endodermal sinus tumor of the ovary, previously called a yolk sac tumor, is the second most common germ cell neoplasm, occurring in approximately 20% of cases.
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[edit] Main types of ovarian cancer
There are three main types of ovarian cancer.
- Germ cell tumors: this type from the cells that produce the ova.
- Stromal tumors: from connective tissue cells.
- Epithelial tumors: starting from the cells that cover the outer surface of the ovary. These are the most common type of ovarian cancers.
[edit] Epidemiology
Although 20% to 25% of all benign and malignant ovarian neoplasms are of germ cell origin, only about 3% of these tumors are malignant. Germ cell malignancies account for less than 5% of all ovarian cancers in Western countries but they represent up to 15% of ovarian cancers in Asian and black societies, where epithelial ovarian cancers are much less common.
[edit] Symptoms, Signs, and Diagnosis
Functional effects of germ cell or stromal tumors include hyperthyroidism, feminization, and virilization. However, benign functional cysts are common in young women; vaginal sonography or reexamination after 6 wk helps differentiate cysts from tumors.
Mature Cystic Teratoma. Benign cystic teratomas or dermoid cysts are the most common germ cell tumors and in this case all tissue is mature and there is no mitotic activity. Patients may be asymptomatic or present abdomino-pelvic pain or increasing abdominal girth.
Dysgerminomas. Dysgerminomas are the most frequent malignant germ cell tumors in young women (80% of cases). They are rarely pure dysgerminomas but are often mixed with other cell types and synciotrophoblastic types secreting hCG.
Endodermal Sinus Tumors or Yolk Sac Tumors. These are an association of extra-embryonic mesodermal cells and endodermal cells. The mean age at diagnosis is 19 years and the incidence appears to increase with age.
Gonadoblastoma of the ovary is a rare neoplasm composed of nests of germ cells and sex cord derivatives that are surrounded by connective tissue stroma.
Other Tumors. Other tumors include embryonic carcinomas consisting of extra-embryonic and embryonic teratoma-type pluripotential cells.
[edit] Laboratory Evaluation
When an ovarian malignancy is included in the list of diagnostic possibilities, a limited number of laboratory tests are indicated. A complete blood count (CBC) and serum electrolyte test should be obtained in all patients. Coagulation tests are not indicated in the absence of a suggestive history of bleeding after minor trauma or increased bruisability. Similarly, routine liver function tests are rarely helpful.
The serum hCG level should be measured in any female in whom pregnancy is a possibility. In addition, a serum AFP and lactate dehydrogenase (LDH) should be measured in young girls and adolescents who present with adnexal masses because the younger the patient, the greater the likelihood of a malignant germ cell tumor.
[edit] Treatment
In contrast to epithelial ovarian neoplasms, most germ cell neoplasms are early stage at the time of diagnosis. This observation, in conjunction with the low incidence of bilaterality and the young age of most patients, for whom future fertility is an issue, influences the surgical management of this group of neoplasms. For young women with a germ cell neoplasm of the ovary, removal of the involved adnexa with preservation of the normal-appearing contralateral adnexa and uterus is generally advocated. In view of the low incidence of bilaterality, biopsy or bivalving the contralateral ovary is not recommended because of the risk of peritubal and periovarian adhesions. Complete surgical staging of germ cell neoplasms is the same as for epithelial ovarian neoplasms and should be performed in all cases.
Most patients with advanced-stage germ cell malignancies or high-risk early-stage disease can be cured with combination chemotherapy. Bleomycin, etoposide, and cisplatin are most commonly used.
[edit] Radiation Therapy
With respect to germ cell neoplasms, radiation therapy has been used successfully in the treatment of patients with dysgerminoma.
[edit] References
- Christian J, Thomas H: Ovarian cancer chemotherapy. Cancer Treat Rev 2001;27:99.
- Runnebaum IB, Stickeler E: Epidemiological and molecular aspects of ovarian cancer risk. J Cancer Res Clin Oncol 2001;127:73.
- Angeles A. Alvarez, Daniel L. Clarke-Pearson Germ Cell Malignancies - Nonepithelial Ovarian Cancer
- Germ Cell Tumors - Ovarian Masses in Adolescent Girls
[edit] Sources
- Angeles A. Alvarez and Daniel L. Clarke-Pearson Ovarian Cancer [for patients]
- Jonathan S. Berek, MD Robert C. Bast Jr, MD Ovarian Cancer [professionals]
